Separated pocket spring mattress

ABSTRACT

A spring mattress comprising a plurality of interconnected coil springs ( 1 ) enclosed in covers ( 2 ), known as a pocket-spring mattress, is described, wherein at least two springs that are located adjacent to one another are spaced apart by an interjacent separation distance (SA), said separation distance exceeding approximately 10% of the diameter of the largest one of the spiral turns of the adjacent springs. Also described is a method of manufacturing a corresponding mattress.

TECHNICAL FIELD OF INVENTION

[0001] The present invention relates to a spring mattress of the kindwherein the springs are enclosed in covers, known as a pocket-springmattress, and to method of manufacturing a mattress of this kind.

BACKGROUND OF THE INVENTION

[0002] One common technique of manufacturing spring mattress is the oneknown as the pocket technique. According to this technique, the springsare enclosed in pockets, i.e. they are enclosed individually by a covermaterial. Owing to this arrangement, the springs become relativelyresilient individually, such that each spring may flex separatelywithout affecting adjacent springs, which increases the user's comfort,since the load will be distributed more evenly across the surface thatreceives the load.

[0003] One problem inherent in this type of mattresses is, however thatthey are a great deal more expensive to manufacture than many othertypes of spring mattresses.

[0004] Consequently, there is a need for a mattress that is easierand/or cheaper to manufacture while at the same time offering comfort atleast equivalent to that found in prior-art pocket-spring mattresses.

OBJECT OF THE INVENTION

[0005] One of the objects of the present invention therefore is toprovide a spring mattress of the kind defined in the introduction, and amethod of manufacturing said mattress, by means of which thedisadvantages referred to above are completely or at least partlyremoved.

[0006] This object is achieved in a spring mattress and by means of amethod of manufacturing said mattress in the manner defined in theappended claims.

SUMMARY OF THE INVENTION

[0007] The invention relates to a spring mattress comprising a pluralityof interconnected coil springs enclosed in covers, at least two springslocated adjacent to one another being spaced apart by an interjacentseparation distance, said separation distance exceeding approximately10% of the diameter of the largest one of the spiral turns of theadjacent springs.

[0008] In this manner, a spring mattress is obtained which at least insome places exhibits separation distances between the springs, makingthe mattress less compact. Consequently, fewer springs are required, theoperational step of enclosing the springs in covers becomes easier andso on. The mattress thus becomes both easier and less expensive tomanufacture. Surprisingly enough it has been found, however that theproperties of the mattress are not noticeably affected from being lesscompact but that essentially the same qualities of comfort are achievedin the inventive mattress as in conventional pocket-spring mattresses.In fact, it has even been found that in some cases the increaseddistance between the springs adds to the individual resilience of thespring, which increases comfort, since each individual spring is able tosupport loads comparatively independently.

[0009] In prior-art pocket-spring mattresses the springs may be spacedapart by a certain separation distance but normally this distanceamounts to a few millimeters only, sufficient to accommodate a thin weldseam. In addition, in prior-art mattress structures the number ofsprings may be reduced by using larger springs. In practical terms, thissolution is, however unsuitable as doing so substantially affects theproperties of the mattress.

[0010] It is particularly preferable that the separation distance islarger than 15% of the largest one of the spiral turns of the springsthat are located next to one another, and preferably larger than 20%. Inaddition, it is preferable that the separation distance is larger than 1cm. In this manner a less compact mattress is obtained, which makes thelatter even less expensive and more simple to manufacture.

[0011] It is likewise preferable that the covers enclosing adjacentsprings are spaced apart by an intermediate separation distance (SB)that exceeds 10% of the diameter of the largest one of the spiral turnsof the adjacent springs, and preferably exceeds 15% and most preferablyexceeds 20%.

[0012] In this manner, much of the separation distance will consist ofmaterial located externally of the enclosing cover parts, which does notnegatively affect the enclosure-dependant stability offered the springs.

[0013] A particularly preferred feature is to form the mattress with aplurality of springs that are arranged in strips made from the covermaterial, several such strips being joined together. In this manner, theseparation feature is obtained in that at least most, and preferablyessentially all springs arranged in at least one strip are separatedfrom one another. This is achieved in that the separation distance isformed by joining-together the cover material in a lengthwise extendedinterconnection on each side of the springs or by providing twointerconnection lines for joining-together the cover material on eachside of the springs, said lines being spaced apart in the longitudinaldirection of the strips.

[0014] This makes it easy to achieve the separation feature withouthaving to supply additional separation material.

[0015] It is particularly preferred that mattresses in accordance withthe invention have a spring density in at least one lengthwisedirection, in which separation distances are provided, of less than 15springs per meter, and preferably less than 13 springs per meter. Theresulting mattress is a great deal more simple and less expensive thanconventional mattresses, which as a rule have 30 springs and more in thelengthwise direction of the mattress.

[0016] The invention likewise concerns a method of manufacturing amattress of the kind defined above. The method comprises the steps ofenclosing the springs in a cover material; and interconnecting thesprings with one another, whereby at least two springs that are locatedadjacent to one another are interconnected in such a manner that aninterjacent separation distance is formed between the springs, saidseparation distance exceeding about 10% of the diameter of the largestone of the spiral turns of springs located adjacent to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In the annexed drawings:

[0018]FIG. 1 shows a spring mattress designed in conformity with theinvention;

[0019]FIG. 2 shows a strip comprising separated springs in accordancewith a first embodiment to be used in a mattress in accordance with theinvention; and

[0020]FIG. 3 shows a strip comprising separated springs in accordancewith a second embodiment to be used in a mattress in accordance with theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] The invention will be described in the following for exemplifyingpurposes by way of one embodiment and with reference to the accompanyingdrawings.

[0022] A spring mattress in accordance with the invention comprises aplurality of interconnected coil springs 1, which are enclosed in covers2. Suitably, the cover is made from a preferably weldable textile fabricbut other materials, such as various types of plastic material couldequally well be used. It is likewise possible to use non-weldabletextile fabrics, such as cotton fabrics. Normally, strips 3 ofinterconnected, cover-enclosed pocket springs are manufacturedautomatically, whereupon the strips are cut into suitable lengths andjoined together side by side to form mattresses.

[0023] Preferably, the covers are dimensioned to ensure that the maximumenclosed height amounts to at least 3 cm and preferably to at least 5cm.

[0024] Coil springs of many different sizes could be used in conjunctionwith the present invention, and in principle any desired spring size,large or small, may be used. Preferably, however springs are used havinga diameter of 2-10 cm, and most preferably a diameter of 6 cm.Preferably the springs comprises at least four spiral turns andpreferably fewer than 10 spiral turns. In addition, it is an advantageto manufacture the springs from helically coiled wires having athickness in the range between 0.5 and 3.00 mm and preferably a wirethickness in the range of 1.5 to 2.2 mm.

[0025] In the spring mattress in accordance with the invention at leastat least two adjacent springs are spaced apart by an interjacentseparation distance SA, said separation distance exceeding 10% of thediameter of the largest one of the spiral turns of the adjacent springs,and preferably it exceeds 15% of the diameter of the largest one of thespiral turns of adjacent springs, and preferably exceeds 20%. Inaddition, the separation distance preferably exceeds 1 cm. Preferablyalso the covers enclosing adjacent springs are spaced apart by anintermediate separation distance SB, said separation distance exceeding10% of the diameter of the largest one of the spiral turns of theadjacent springs, and preferably exceeding 15% and most preferablyexceeding 20%. In addition, the separation distance SB preferably alsois larger than 1 cm.

[0026] These separation distances preferably are arranged betweenessentially all springs in the lengthwise direction of the mattress.This may be achieved by arranging two joining-together lines 4 that arespaced apart in the lengthwise direction of the strips as illustrated inFIG. 2, so as to join-together the cover material on each side of thesprings. Alternatively, it is instead possible to provide one or severalinterconnection means 5 to join-together the cover material in aninterconnection extended in the lengthwise direction of the strips oneach side of the springs, which interconnection means could be e.g. awide weld seam, as illustrated in FIG. 3. Likewise, it is possible touse continuous welding lines instead of spot-welded seams, as shown inFIGS. 2 and 3, Other types of interconnections are possible too, such asone or several stitched seams.

[0027] The springs could, however also be separated in other ways, suchas by introducing separation members or the like between the strips.

[0028] The invention makes it possible to use less than 30 springs andpreferably about 25 springs and most preferably about 22 springs inmattresses having a length in excess of 180 cm. It is also preferablethat in the mattresses in accordance with the invention the density ofsprings in the lengthwise direction or directions, in which theseparation distances are provided, is less than 15 springs per meter andpreferably is less than 13 springs per meter.

[0029] In the manufacture of mattresses in accordance with theinvention, the springs are enclosed in a cover material. Thereafter, orin conjunction with the enclosing step, the springs are interconnectedwith one another to form mattresses. In this operation, care is taken toensure that at least two springs located adjacent to one another areinterconnected in such a manner that an interjacent spring-separationdistance is formed between the springs the length of which exceeds 10%of the diameter of the largest one of the spiral turns of the adjacentsprings.

[0030] It is particularly advantageous to interconnect the springs byarranging a plurality of springs in strips formed by the cover materialand to join-together several strips of this kind. The separation of thesprings may be effected by joining-together the cover material in alengthwise extended interconnection of the strips on each side of thesprings, or by arranging two interconnection lines for joining-togetherthe cover material on each side of the springs, which are separated inthe lengthwise direction of the strips.

[0031] As already mentioned the covers comprising springs preferably arearranged in successive rows, whereupon such rows are attached to oneanother side by side as indicated in FIG. 1. Preferably, the rows areattached to one another in 2-3 vertically spaced attachment pointsopposite the associated spring. A larger or smaller number of attachmentpoints could of course also be used. It is likewise possible to use onelong attachment line extending essentially in parallel with thelongitudinal direction of the springs instead of several, shorterattachment points. It is likewise possible to join-together the stripsby means of a string of glue or the like extending in the direction ofextension of the strips. The joining-together of rows side by side insuccession could be effected by welding or gluing, as mentionedpreviously. Other alternative joining-together means could be used, suchas clamps, Velcro tapes or some other suitable joining-together methodbe used. It is likewise possible to attach the rows to one another byusing interconnecting sheets at the upper and lower faces of thesprings. The sheets could be made from a textile material and beattached by means of gluing or welding.

[0032] By joining-together the strips in this way opposite the springsin the respective strip the separation distances will be positioned inalignment with one another. This position is the preferred one, althoughit is likewise possible to arrange the strips in such a manner that thesprings will be staggered, i.e. positioned offset relative to oneanother. In the latter case the springs as a whole may be arranged moredensely across the mattress than is the case in conventionalpocket-spring mattresses, although as a rule this is not desirable.

[0033] It is also possible to use differently-sized separation distancesin different zones or areas of the mattress and to use e.g. largerseparation distances in areas that in normal use of the mattress areless exposed to load, and smaller separation distances in areas exposedto more heavy loads.

[0034] The mattress in accordance with the invention offers resilienceproperties equivalent to those achieved in conventional pocket-springmattresses, providing the same firmness, comfort and so on. Possiblysomewhat harder springs than normal may be used to increase the mattressfirmness.

[0035] The invention has been described above with reference to oneembodiment. Several varieties of the invention are possible, however.For example, other cover materials may be used as also differently-sizedsprings, and so on. Such close varieties should be considered to bewithin the scope of protection of the invention as defined in theappended claims.

1. A spring mattress comprising a plurality of interconnected coilsprings (1) enclosed in covers (2), characterised in that at least twosprings that are located adjacent to one another are spaced apart by aninterjacent separation distance (SA), said separation distance exceedingapproximately 10% of the diameter of the largest one of the spiral turnsof the adjacent springs.
 2. A spring mattress as claimed in claim 1,wherein said separation distance exceeds 15% of the diameter of thelargest one of the spiral turns of the adjacent springs, and preferablyexceeds 20%.
 3. A spring mattress as claimed in claim 1 or 2, whereinthe separation distance exceeds 1 cm.
 4. A spring mattress as claimed inany one of claims 1-3, wherein the covers enclosing adjacent springs arespaced apart by an interjacent separation distance (SB), said separationdistance exceeding 10% of the diameter of the largest one of the spiralturns of the adjacent springs, and preferably exceeding 15% and mostpreferably exceeding 20%.
 5. A spring mattress as claimed in any one ofclaims 1-4, wherein it comprises a plurality of springs arranged instrips of the cover material, several strips of this kind being joinedtogether.
 6. A spring mattress as claimed in claim 5, wherein at leastmost springs and preferably essentially all springs in at least onestrip are separated from one another.
 7. A spring mattress as claimed inclaim 6, wherein the springs in a majority of the strips and preferablyin essentially all strips are separated from one another.
 8. A springmattress as claimed in any one of claims 5-7, wherein the separationdistance is achieved by joining-together the cover material in a jointextended in the lengthwise direction of the strips on each side of thesprings.
 9. A spring mattress as claimed in any one of claims 5-7,wherein the separation distance is achieved by two interconnection linesfor joining-together the cover material on each side of the springs,said lines being spaced apart in the lengthwise direction of the strips.10. A spring mattress as claimed in any one of claims 5-9, wherein thestrips are arranged in parallel with the lengthwise direction of themattress.
 11. A spring mattress as claimed in claim 10, wherein thedensity of springs in at least one lengthwise direction, in whichseparation distances are provided, is less than 15 springs per meter,and preferably less than 13 springs per meter.
 12. A spring mattress asclaimed in any one of the preceding claims, wherein the spiral turn ofthe springs having the largest diameter has a diameter size of 2-10 cm,and preferably about 6 cm.
 13. A spring mattress as claimed in any oneof the preceding claims, wherein the springs comprise at least fourspiral turns, and preferably fewer than 10 spiral turns.
 14. A springmattress as claimed in any one of the preceding claims, wherein thehelically coiled wires of the springs have a thickness in the range ofbetween 0.5 and 3.0 mm, and preferably a wire thickness in the range ofbetween 1.5 and 2.2 mm.
 15. A spring matter as claimed in any one of thepreceding claims, wherein the cover is made from a preferably weldabletextile fabric.
 16. A method of manufacturing a spring mattress of thekind comprising a plurality of interconnected coil springs (1), whichare enclosed in covers (2), comprising the steps of: enclosing thesprings in a cover material; and interconnecting the springs with oneanother; characterised by interconnecting at least two springs locatedadjacent to one another in such a manner that an interjacent separationdistance is formed between the springs, said separation distanceexceeding about 10% of the diameter of the largest one of the spiralturns of springs located adjacent to one another.
 17. A method asclaimed in claim 16, wherein the separation distance exceeds 15% of thediameter of the largest one of the spiral turns of springs locatedadjacent to one another, and preferably exceeds 20%.
 18. A method asclaimed in claim 16 or 17, wherein said separation distance is largerthan 1 cm.
 19. A method as claimed in any one of claims 16-18, whereinthe step of interconnecting the springs comprises arranging a pluralityof springs in strips made by the cover material, several such stripsbeing joined together.
 20. A method as claimed in claim 19, whereinseparating the springs is achieved by joining-together the covermaterial with a joint with an extension in the lengthwise direction ofthe strips on each side of the springs.
 21. A method as claimed in claim19, wherein the separation distance is achieved by two interconnectionlines for joining-together the cover material on each side of thesprings, said lines being spaced apart in the lengthwise direction ofthe strips.
 22. A method as claimed in any one of claims 20-21, whereinthe cover is made from a weldable material, and preferably from atextile material, said joining-together being effected by welding.